# include <iostream>
#include <functional>
using namespace std;
void test01(){
    negate<int>n;
    cout<<n(50)<<endl;
}
void test02(){
    plus<int>p;
    cout<<p(10,20)<<endl;
}
int main() {
test01();
test02();
    system("pause");
    return 0;
}
